On August 5, 2010, an enormous chunk of ice, roughly 97 square miles (251 square kilometers) in size, broke off the Petermann Glacier, along the northwestern coast of Greenland. The glacier lost about one-quarter of its 70-kilometer (40-mile) long floating ice shelf, the Northern Hemisphere's largest. It's not unusual for large icebergs to calve off the Petermann Glacier, but this new one is the largest to form in the Arctic since 1962.